Fluid-pressure control



Nov. 1,1927. 1,647,135

. J. F. JOHNSON FLUID PRESSURE CONTROL Filed Aug. 8, 1921 JR'Ja/msonINVENTOR ATTORNEY Patented, Nov. 1, 1927.

' U I E S AT S JOSIAH r. JoHNsoN, on swanrinvronn, PENNSYLVANIA,

assume mo wns'rlNo- SYLVANIA.

FLUID-PRESSURE coNTRoL.

Application filed August 8,1921. Serial No. 490,749.

This invention relates to lubricating systems and more particularly topressure lu-' bricating systems for bearings and it has for an objectthe provision of apparatus or" the character designated which shall beresponsive to the pressure in the lubricating system to maintain anapproximatelyconstant p re determined pressure on the lubricant in thesystem. Y It has for a further object the provision of apparatusassociated with a fluid-pressure lubricating system which shall serveboth to regulate the pressure of the lubricant in the system and torelievethe system of excess lubrican'tQ 7 Q As anillustration of oneform which my invention may take, reference'm'ay behad to theaccompanying drawing in which the. single figure is a diagrammatic view,partially in section and partially in elevation, of apparatus embodyingmy invention.

desired to have an adequate supply of oil The present inventioncontemplates a pressure lubricating system to shaft bearings in whichthe lubricant, hereinafter, for convenience,termed oil, is supplied by amain pump and an associated auxiliary pump. I Such a system isparticularly adaptable to "power-developing units such, for example, as

steam turbines. i

During normal operation, the; main oil pump is employed to maintainapproximately a predetermined oil pressure as, for example, five poundsper square inch, on the bearings. One difficulty heretofore experiencedin installations of this character has been that a material drop inbearing oil'pre'ssure obtains upon starting and stopping the ma chine,especially if a rotary main pump is used, since the output of such apump varies ,with the square of itsspeed. During starting or stopping,however, it is particularly 7 on the bearings to prevent scoring.

Furthermore, for a short period following starting, the oil has a lowertemperaturethan the normal running temperature and does not flow asfreely through the bearings, whilethe volume delivered by the pump isapproximately constant. This results in the development of abnormallyhigh back pressure. The purpose of my invention is to provideacoordinated regulatort'or the main pump and controlling mechanism' forthe auxiliary pump, which the auxiliary pump may be operated inconjunction with the main pump to supply the requisite amount ot Oll tothe bearings at a substantially constant pressure underall conditions ofshaft speed and of oilviscosity. It is also a purpose of my invention toprovide a pressure regulator which is easily kept in operable conditionand which may be readily tested at frequent intervals.

Referring to the drawing for a more detailed understanding of invention,I

show a constant-pressure lubricating system for bearings in whichlOindica'tes the main 011 pressure pump and llan auxiliary pump arrangedto supply 011 to the bearings o1 a machine 12, which may be a turbine,or a from an independent source of power and may be areciprocatingmotive-fluid pump, such as an ordinary steam pump. v Oil isconducted to the machine v12-from'the main and auxiliary pumps 10 and llby-conduits 13 and 14 which deliver into a conduit 15. The conduits 13and 14 are provided with checkvalves 16 and 17 to prevent the back flowof oil therethrough. Oil drained from the bearings is conducted; to a"suitable reservoir 18 bygravity'through the conduit 1 and oil from thereservoir is conducted to the pumps 0 10 and 11' through conduits 24:and 30. respectively. I i i To enable the main and auxiliary oil pumpsto cooperate efiect ively, I inter-pose a regulator 20 in the bearing'oil supply system. The regulator 20 comprises a casing 21 III which 1slocated a cylindrical chamber 22,

the lower portion of which is connected to the bearing oil supply by aconduit 23. The. I

upper end of the chamber 22 is connected to the atmosphere. The casing21 is also pro- 'vided with a'passage 25, communicating piston 28provided with a stem member 29 projecting upwardly through a cover 31for the chamber 22. The piston 28, which close- \ly fits the chamber 22,is subjected to the pressure of the oil in the system, which urges theplston in an upward direction.

The stem 29 is provided at its upper extremity with suitable means, suchas weights 32, which opposes upward movement of the pis ton 28. The stem29 is also provided at a point below the weights with a pair of spacedshoulders 33 which constitute stops for a purpose which will presentlyappear.

-Motive fluid admitted to the auxiliary pump 11 through the conduit 35is controlled in any suitable manner, as for example, by balanced valve36. The valve 36 actuated by a stem portion 37, which is connected to arocker lever 38, pivoted at 39. The other end of the rocker lever 38 isprovided with a fork 41 embracing the stem 29 and engaging between thespaced stops 33, thus forming a lost motion connection therewith. t isapparent that the stem 29 is freely rotatable between the fork 41. Bythe occasional rotation of the stem 29 the operator of the apparatus isinsured that the piston 28 is not sticking in its cylinder 22, thisaction permitting substantially frictionless vertical movement of thepiston, as in the ordinary gauge-testing operation.

The valve stem 37 is urged in a direction to close the valve 36 by anysuitable means, such as a spring 42. The spring 42 serves to effectpositive closing of the valve 36 when permitted to do so by the rockerlever 38.

The operation of the above described apparatus is as follows: l/Vhentheshaft of the machine 12 is rotating at normal speed, the pump 10 isdelivering oil under pressure to the shaft bearing through the conduit15, and to the chamber 22 through the conduit 23, thus causing thepiston 28 to rise against the action of weights 32 an amount determinedby the pressure in the chamber. The weights 32 are so chosen that undernormal operating conditions, the piston uncovers the entrance to passage25, allowing the excess oil pumped to return to the reservoir 18through'the conduit 26; the amount of oil so by-passed being visiblethrough the sight glass 27.

When, for any reason, the pressure of the oil delivered by the main pumpdiminishes, the weights 32 force the piston 28 downwardly and close theby-pass'25. the piston 28 continue to move downwardly, the upper, stop33 on the stem 29 contacts with the fork 41 on the lever 38 and moves itdownward against the action of the spring 42. This raises the valve stem37 of the balanced valve 36, thereby admitting mo- Should tive fluid tothe auxiliary pump 11, and.

causing said pump to start up and deliver oil to maintain the pressurewithin the systern.

As the auxiliary pump restores the oil pressure within the system, thepiston moves upwardly and the spring 42 assistsin positively closing theauxiliary pump valve 36. During the operation of starting or stoppingthe machine 12, when the speed of the main pump s too low-to maintain asuflicient volume of oil on the bearings, the

valve 36 is wide open and'tl'ie auxiliary pump 11 supplies, inconsequence, the defioit of oil. After the machine 12 has come to rest,the pump llscan be shut down in any well known manner, as by closing amanual valve in the motive fluid supply pipe thereto.

Nhile I have shown my invention in but constant pressure in the system,and means responsive to the pressure changes in the system for causingexcess lubricant to bypass and to automatically startvthe'auxiliary pumpupon a diminution of pressure in the system.

2. In combination in a lubricating system,

main supply means to supply lubricant to r the system, anindependently-driven auxiliary means associated with the main supplymeans to maintain a constant pressure in the system, means forby-passing excess fluid delivered by the main supply means, and

means for starting the auxiliary supply means on a diminution ofpressure by a predetermined amount.

3. In a lubricating system having main supply means to supply lubricantto the system at varying pressures and independent auxiliary supplymeansassociated wlth the main supply means to maintain a substantiallyconstant pressure in the system, means responsive to the pressure in thesystem for relieving any excess fluid pressure caused by the main supplymeans and for introducing lubricant from the auxiliary supply means intothe system upon a diminution of pressure in the system.

4. In combination in a lubricating system, main supply means to supplylubricant to the system, an auxiliary supply means associated with themain supply means to Ill) 5. In a constant fluid pressure systemcomprising a main supply means and an auxiliary supply means, a pressurecontrolled bypass valve associated with the main supply means and meansassociated with the by-pass valve for positively controlling theauxiliary supply means to maintain a constant pressure in the system.

6. In a constant fluid pressure system comprising a main supply meansand an auxiliary supply means, a control mechanism for regulatingtheoutput of the auxiliary supply means in accordance with the pressuremaintained in the system by the main supply means, and means associatedwith the control mechanism for by-passing excess fluid.

7. In a constant fluid pressure system having a main supply means and anauxiliary supply means, a control mechanism for the system including achamber-in communication with the lubricating system, a fluid actuatedpiston in the chamber, and means comnunicating with the chamber andcontrolled by the piston to discharge the excess output of the mainfluid supply means.

8. In a pressure lubricating system, in combination, a main pump, anauxiliary pump associated therewith and independently driven, a pressurerelief by-pass valve including a reciprocatory piston and means operatedby said piston to control the auxiliary pump whereby an approximatelyconstant pressure is maintained in the system.

9. In a fluid pressure system having a main pump and an auxiliary pumpassociated therewith, in combination, pressure relief means including apiston subjected to pressure in the system, a bypass controlled by thepiston and means actuated by the piston to control the operation of theauxiliary pump to maintain approximately constant pressure in thesystem.

10. In a constant fluid pressure system having a main supply means,.anauxiliary supply means, a control device for the auxiliary supply means,and a regulator for the system comprising a casing chamber communicatingtherewith, a movable fluid actuated piston in the casing, a fluidby-pass for the system communicating with the casing and controlled bythe piston, and means including a lost mot-ion connection actuated froman in by the piston to operate the control device for the auxiliarysupply means.

11. In a control device for a constant fluid pressure system including amain pump and an independently driven auxiliary pump, a fluid bypassvalve comprising a reciprocatory piston, means balancing the pistonagainst the fluid pressure of thesystem, and

control means including a balanced valve for the motive fluid of theauxiliary pump, said control means being operated by the piston througha. lost motion connection.

12. In a fluid pressure lubricating system for rotary shaft bearings, incombination, a rotary pump driven from the shaft, an independentlydriven auxiliary pump normally inoperative, and control means responsiveto fluid pressure in the system, whereby excess fluid is by-passed atnormal pressure and the auxiliary supply means is placed in operation ondiminishing pressure. p

13. In a fluid pressure lubricating s 'stem, in combination, a mainrotary pump,

an auxiliary reciprocatory pump independently driven and normallyinoperative, control means responsive to fluid pressure in the systemincluding a by-pass for excessvfluid and means actuated by the controlmeans to place the auxiliary pumpin operation onfia predetermineddiminution of pressure. a

14. In a fluid pressure system, in combination, a main ump, an auxiliarypump driven dependent source of power, a pressure regulator directlycontrolling the maximum pressure in the system, and means actuated bythe regulator and controlling the input of power to the auxiliary pumpto maintain approximately constant pressure in the system.

15. In a shaft bearing lubricating system,

a main pump driven from the shaft that is lubricated, an auxiliary pumpdriven from an independent source of power and means responsive tolubricantpressure controlling the supply of power to the auxiliary pump.

16. In a shaft-bearing lubricating system, a main pump driven from theshaft that is lubricated and capable ofmaintaining a predeterminedpressure at'normal speeds,an independently driven auxiliary pump tomaintain the predetermined pressure at low shaft speeds and automaticpressure-responsive means controlling the auxiliary pump whereby thepredetermined pressure is approximately maintained at all shaft speeds.

In testimony whereof, I have hereunto subscribed my name this second dayof August, 1921.

JOSIAH r. JOHNSON.

